Information on the number of Sri Lankan nationals that have been returned from the UK to Sri Lanka, is available in table rt_04 (returns data tables, volume 4) in ‘Immigration Statistics, year ending June 2018’, available from the GOV.uk website at:
The data can be broken down by asylum and non-asylum related returns. Asylum-related returns relate to cases where there has been an asylum claim at some stage prior to the return. This will include asylum seekers whose asylum claims have been refused, and who have exhausted any rights of appeal, those retuned under third country provisions, as well as those granted asylum/protection, but removed for other reasons (such as criminality).
Information for October to December 2018 will be available in February 2019.